2aPAb12. Diffuse field decay curvature for material characterization.

Session: Tuesday Morning, May 14

Time: 11:30

A new quantitative technique is proposed for determining both the
concentration and spatial extent of viscous dissipation in dynamic systems. When
dissipation is distributed unevenly within a system, nonexponential response
decays can result within certain frequency ranges. Unlike typical exponential
decays that carry volume averaged information about the strength of dissipation,
nonexponential decays carry information about both the strength and distribution
of dissipation in the system. Two parameters describe the nonexponential decay
process and can be directly related to the strength and spatial extent of the
dissipation. It is proposed that fitting observed nonexponential decays to the
predicted model may provide a method for the nondestructive determination of
both the extent and severity of dissipation causing defects in materials. The
presented work concentrates on acoustic systems and provides a test of the
proposed concept. Theoretical predictions are presented and compared with
numerical experiments to determine the effectiveness of the proposed approach.